Recently revised statistics show the number of individuals living with HIV at over 33 million worldwide, with 68% being in sub-Saharan Africa. Current HIV prevention methods, such as condom use, monogamy and abstinence, are not always feasible. The need for improved HIV preventative technologies remains urgent. The development of topical microbicides represents a new and exciting field in the prevention of sexually transmitted diseases. Of these, application of live probiotic bacterial microbicides (PBM) represents a promising preventative method. Our ultimate goal is to develop potent optimized multistrain thermostable and easily deliverable probiotic vaginal topical microbicides. To achieve this goal we will stabilize vaginal probiotics for long-term storage at high ambient temperatures and short term survival at temperatures required for quick dissolve film manufacturing (60C and above). The cornerstones of this proposal are: 1) Preservation by Vaporization (PBV) - an innovative, patent pending method of dry-stabilizing probiotics bacteria and other fragile biologicals at high ambient temperatures, and 2) Quick-dissolve thin film technology that is being optimized to deliver conventional vaginal microbicides. The strategy can be described briefly as, to occupy the vaginal epithelium and provide a long lasting protective environment against HIV, BV, and STI acquisition small (10-50 m) glassy sugar particles containing PBV vaginal probiotic bacteria will be formulated into thin films which utilize a water soluble polymer base. Thin films offer a unique delivery platform which has a number of advantages over other dosage forms. In a recent study comparing women's preference between films, tablets and ovules, the film dosage form was shown to have greatest acceptability among women studied. We believe that women will prefer using a vaginal film over other potential methods of probiotic microbicide delivery especially if a long-acting effect of the bacteria colonizing vaginal epithelium allows for less frequent use. Biologic properties of PBM after long-term storage at ambient temperatures will be characterized using cell culture models of vaginal and cervical epithelium. PUBLIC HEALTH RELEVANCE: As the number of individuals living with HIV continues to rise and a feminization of the epidemic is occurring. At the end of 2007 women accounted for 50% of all adults living with HIV worldwide and 61% in sub-Saharan Africa. Of new HIV cases at least half are in individuals less than 25 years of age and of those aged 13-19 54% are teenage girls. For this reason there is a desperate need for the development of an effective female controlled microbicide product to protect against acquisition of HIV. The innate vaginal flora provide a natural defensive barrier to infection hence a probiotic microbicide provides a promising strategy for prevention. This project serves to evaluate a strategy to overcome two barriers to its successful application, long term bacterial preservation at relevant environmental conditions and a user acceptable stable delivery system for vaginal administration. The innovative combination of preservation by vaporization and thin film dosage forms with use of multi-strain formulations provides a unique technology which can serve to overcome existing barriers to provide a safe and effective probiotic microbicide product to protect women from acquisition of HIV.